Ball circulation type of spiral gearing

Abstract

A ball circulation type of screw and nut spiral gearing having a ball return tube establishing a passage between the ball guiding channels of the gearing within an elongated peripheral slot formed in the nut. A spacer is disposed between the ball return tube and a cover wall surrounding the nut to maintain the spacer and ball return tube in proper assembled positions. The spacer and ball return tube are interengaged to form a preassembly unit for joint installation into the peripheral slot of nut during assembly of the gearing.

What is claimed is: 
     
       1. In a ball-circulation type of spiral gearing having a nut (1), a ball return tube (3) exclusively establishing a return passage between ball guiding channels of the gearing, within an elongated peripheral slot (2) in the nut, a spacer (9) in engagement with the ball return tube in spaced relation to the ball guiding channels and a cover (8) enclosing the spacer and the ball return tube within the unit, the improvement residing in means (10,11) for holding the spacer and the ball return tube preassembled as a unit independently of the spiral gearing and insertable into the nut through said slot, and means for preventing disassembly of said unit after insertion into the peripheral slot. 
     
     
       2. The combination of claim 1, wherein the ball return tube includes two half sectons held together by the spacer in the preassembled unit. 
     
     
       3. The combination of claim 1 wherein said nut has a outer surface through which the slot extends and on which the cover is supported, said ball return tube being radially spaced from the outer surface by the spacer. 
     
     
       4. In a ball-circulation type of spiral gearing having a nut (1) and a ball return tube (3) establishing a return passage, between ball guiding channels of the gearing, within an elongated peripheral slot (2) in the nut, and a spacer (9) located between the ball return tube and a cover (8) surrounding the nut, the improvement residing in means (l0, 11) for holding the spacer and the ball return tube preassembled as a unit independently of the spiral gearing and means for preventing disassembly of said unit after insertion into the peripheral slot, said holding means including a pair of elastic flaps (l0, 11) formed on the spacer having projections (12, 13) embracing the ball return tube. 
     
     
       5. The combination of claim 4, wherein the spacer is made of a plastic material. 
     
     
       6. The combination of claim 4, wherein the ball return tube includes two half sections (6, 7) held together by the spacer. 
     
     
       7. The combination of claim 6, wherein said disassembly preventing means comprises an internal surface of the peripheral slot dimensioned relative to the spacer to prevent outward flexing of the flaps. 
     
     
       8. The combination of claim 4, wherein said disassembly preventing means comprises an internal surface of the peripheral slot engageable with said flaps to prevent outward flexing thereof. 
     
     
       9. The combination of claim 8, wherein the spacer is made of a plastic material. 
     
     
       10. For use in a spiral gearing assembly having a nut (1) provided with a slot (2) extending radially therethrough, a return guide unit received in said slot of the nut for recirculating ball elements, comprising a pair of tube sections (6, 7) between which a ball return passage is formed and spacer means (9) for holding the tube sections assembled independently of the nut, means for locking the tube sections in assembled relation to the spacer means in response to insertion of the return guide unit into the slot, and separable cover means (8) mounted on the nut in engagement with the spacer means exposed through the slot for retaining the assembled return guide unit within the nut to operatively position the ball return passage therein.